<?php $hint = Yii::t('site/general','input keyword'); ?>
<div class="search-input">
    <form action="<?php echo Yii::app()->createUrl('/site/search',array('locale'=>Yii::app()->language)); ?>" method="get" id="search-form">
        <input class="keyword" name="keyword" type="input" id="txt-searched-keyword" onfocus="if(this.value==this.title) this.value='';" onblur="if(this.value=='') this.value=this.title;" value="<?php echo $hint; ?>" title="<?php echo $hint; ?>" /> 
        <input class="button" type="submit" value="search" />
    </form>
</div>

<script type="text/javascript">
$('#search-form').submit(function(){
    var keyword = $.trim($('#txt-searched-keyword').val());
    if (keyword == '<?php echo $hint; ?>')
        keyword = '';
    if (keyword == '')
    {
        alert('<?php echo Yii::t('site/general','please input keyword'); ?>');
        return false;    
    }
});
</script>